For calibration purposes there are today a number of different tools the majority of which includes a rod shaped part and a number of projections aligned along the rod wherein reference surfaces are localized on either or both sides of said projections.
There are tools having essentially even pitch between the projections/reference surfaces and such where the distance between the reference surfaces varies according to set patterns. The known devices are adapted for calibration of measuring tools of a certain kind but are normally not utilized for just any measuring devices for instances such for internal measuring.